U.S. Water News Online
SAN FRANCISCO -- Marking the end of a five-year lawsuit,
Dow Chemical Co. has announced its plan to contribute $3 million for
San Francisco Bay protection while it also cleans up groundwater
contamination at its nearby Pittsburg plant.
The deal, struck between environmental group San Francisco
BayKeeper and Dow, lets the company back out of a previous agreement
to build a groundwater pumping plant to clean up the contamination,
which could have cost the company as much as $100 million.
Instead, Dow says it will use bioremediation cleanup technology in
which nutrients are pumped 100 feet into the ground, stimulating
naturally occurring microbes that will eat away at the contaminants.
"Dow figured out a better mouse trap," BayKeeper spokesman
Jonathan Kaplan said.
The cheaper alternative will cost the company between $15 million
and $20 million to build and $1 million to $2 million per year for
upkeep, according to Dow spokesman Randy Fischback.
In exchange, BayKeeper wanted some of the savings passed on to
them. Dow has agreed to contribute $3 million to BayKeeper, the
Coastal Conservancy and Ducks Unlimited, Inc. to purchase or restore
wetlands at Bel Marin Keys in Marin County, and in Sonoma, Solano,
and Napa counties.
BayKeeper sued Dow in 1997, alleging the Pittsburg plant, which
now produces latex and agricultural chemicals, unlawfully discharged
chlorinated solvents that contaminated groundwater and eventually ran
into San Francisco Bay.
In 1999, the two organizations agreed that Dow would build a plant
to pump the water out of the ground, clean it up and return it. But
that solution turned out to be costly, labor intensive and would have
left waste to be disposed of somewhere else. Dow was fined nearly
$200,000 by the California Regional Water Quality Control Board when
it failed to follow through with those plans.
The company already has started to build "bio-walls" that will
circulate nutrients -- sodium formate, sodium lactate and possibly
even molasses -- in the groundwater. The nutrients will stimulate
bacteria that already exist at the site. The process could take from
a couple of years to decades.
The one-celled bacteria, named Dehalococcoides Ethenogenes, was
discovered by scientists at Cornell University in 1997 and feeds off
of chlorinated solvents, which can be the most difficult to clean up.
The bioremediation technology, which speeds up the bacteria's
feeding process, won't work at all contaminated sites, Fischback
said. The bacteria has to already be present for it to work, and the
ground must be made of sand or loose particles so that the nutrients
can circulate with the water and bacteria.
The technology, typically used to clean spilled petroleum, has
been successful at other sites throughout the nation but rarely has
been attempted on such a large scale, Fischback said. The Pittsburg
plant, 35 miles east of San Francisco, takes up nearly 1,000 acres.
The relatively new technology, however, leaves questions
unanswered. Once the microbes have finished their work and exhausted
their food supply, they could die -- and it's unclear what effect
that would have on the surrounding environment.
"We realize it's cutting-edge technology and that there's some
level of risk," Kaplan said. "We feel it's an acceptable tradeoff."
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